APS Journal April 2017

APRIL 2017

Volume 71

Number 2

AMERICAN POMOLOGICAL SOCIETY F ounded in 1848 I ncorporated in 1887 in M assachusetts

2017-2018

PRESIDENT M. WARMUND

FIRST VICE PRESIDENT M. PRITTS

SECOND VICE PRESIDENT N. BASSIL

RESIDENT AGENT MASSACHUSETTS W. R. AUTIO EDITOR R. P. MARINI

SECRETARY T. EINHORN

EXECUTIVE BOARD

P. HIRST Past President

M. WARMUND President

M. PRITTS 1 st Vice President

N. BASSIL 2 nd Vice President

T. EINHORN Secretary

A. ATUCHA ('14 - '17)

D. CHAVEZ ('15 - '18)

E. HOOVER ('16 - '19)

ADVISORY COMMITTEE 2014-2017 D. KARP C. KAISER G. PECK J. OLMSTEAD D. LAYNE

2015-2018 L. KALCSITS P. CONNER L. WASKO DEVETTER R. HEEREMA E. HELLMAN 2016-2019 R. MORAN E. GARCIA S. YAO M. EHLENFELDT D. BRYLA

CHAIRS OF STANDING COMMITTEES

Editorial R. PERKINS-VEAZIE Wilder Medal Awards J. CLARK

Shepard Award F. TAKEDA

Membership P. HIRST

Nominations P. HIRST

U. P. Hedrick Award E. FALLAHI

Website M. OLMSTEAD

Registration of New Fruit and Nut Cultivars K. GASIC & J. PREECE

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April 2017 Volume 71 CONTENTS Determination of Chemical, Physical and Sensory Characteristics of Apricot Jam from Winter-Hardy Genotypes – Sarah A. Kostick, Neil O. Anderson, Emily Hoover, John Tillman, and Emily Tepe...................... 66 Potential of New Prunus Rootstocks for Managing Armillaria Root Rot Disease in Peach Production – Bruno Casamali and Dario J. Chavez.................................................................................................................... 82 Phenolic Content and Antioxidant Capacity of American Persimmon ( Diospyros virginiana L.) Teas – Hideka Kobayashi, George Antonious, and Kirk Pomper.....................................................................................91 Yield and Quality Characteristics of Several Table Apricot ( Prunus armeniaca L.) Cultivars in the Silifke/Mersin Ecological – A. Bahar and L. Son ................................................................................................ 97 Effect of 1-MCP on Persimmon fruit Quality and Expression of Ethylene Response Genes During Ripening ‒ Do Su Park, Shimeles Tilahun, Jae Yun Heo, Kyong Cheul Park, and Cheon Soon Jeong................................ 103 The Effect of Heat Stress on the Reproductive Structures of Peach – S. Carpenedo, M.C.B. Raseira, D.H. Byrne, and R.C. Franzon................................................................................................. 112 Number 2

Book Review: Kiwifruit: The Genus Actinidia – Ian J. Warrington .................................................................. 119

W.G. Brierley: Pioneering Pomologist of the Prairie – Jared Rubinstein, Emily Hoover, and Julia Kelly..................................................................................................................................................... 121

Instructions to Authors........................................................................................................................................ 128

Published by THE AMERICAN POMOLOGICAL SOCIETY

Journal of the American Pomological Society (ISSN 1527-3741) is published by the American Pomological Society as an annual volume of 4 issues, in January, April, July and October. Membership in the Society includes a volume of the Journal. Most back issues are available at various rates. Paid renewals not received in the office of the Business Manager by January 1 will be temporarily suspended until payment is received. For current membership rates, please consult the Business Manager. Editorial Office: Manuscripts and correspondence concerning editorial matters should be addressed to the Editor: Richard Marini, 203 Tyson Building, Department of Plant Science, University Park, PA 16802-4200 USA; Email: richmarini1@gmail.com. Manuscripts submitted for publication in Journal of the American Pomological Society are accepted after recommendation of at least two editorial reviewers. Guidelines for manuscript preparation are the same as those outlined in the style manual published by the American Society for Horticultural Science for HortScience, found at http://c.ymcdn.com/sites/www.ashs.org/resource/resmgr/files/style_manual.pdf. Postmaster: Send accepted changes to the Business office. Business Office : Correspondence regarding subscriptions, advertising, back issues, and Society membership should be addressed to the Business Office, C/O Heather Hilko, ASHS, 1018 Duke St., Alexandria, VA 22314; Tel 703-836- 4606; Email: ashs@ashs.org Page Charges : A charge of $50.00 per page for members and $65.00 per page ($32.00 per half page) will be made to authors. In addition to the page charge, there will be a charge of $40.00 per page for tables, figures and photographs. Society Affairs : Matters relating to the general operation of the society, awards, committee activities, and meetings should be addressed to Michele Warmund, 1-31 Agriculture Building, Division of Plant Sciences, University of Missouri, Columbia MO 65211; Email:warmundm@missouri.edu. Society Web Site : http://americanpomological.org

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Journal of the American Pomological Society 71(2): 66-81 2017

Determination of Chemical, Physical and Sensory Characteristics of Apricot Jam from Winter-Hardy Genotypes S arah A. K ostick 1 , N eil O. A nderson 2 , E mily H oover 3 , J ohn T illman 4 , and E mily T epe 4 Additional index words: Fruit jams, chemical characterization, flavor, color, sensory evaluation, texture analy- sis, Prunus armeniaca. Abstract Apricots are highly desirable aromatic fresh fruits, although their high respiration rates as climacteric fruit limits their shelf life. Thus, they are often preserved as dried fruits or jams for enjoyment throughout the year. Winter hardy apricots that survive in USDA Zone 4 have never been tested for physicochemical properties and sensorial profiles of their jams; this was the objective for the present study. Fresh fruit from eight winter hardy apricot genotypes were harvested and made into jam; these apricot jams, along with three comparative jam con- trols were tested for soluble solids, pH, titratable acidity, and L*a*b* CIELAB chromaticity coordinates, hue angle, and chrome values. Sensorial profiles were determined in a sensory evaluation panel using the following traits: color, spreadability, texture, fruit pieces, flavor, off flavor, sweetness, bitterness, overall quality, and desire to purchase. ‘Sungold’, ‘Westcott’ and the tart cherry jam control had greater than 60% soluble solids (°Brix). MN 604, MN203, ‘Brookcot’ and ‘Sungold’ apricot jams had the lowest pH levels. The lightest color jam (L*) was ‘Brookcot’ with ‘Debbie’s Gold’ having the yellowest color (b*). The darkest jams were made from MN206 and MN203 similar to the tart cherry control. Panelists were able to discern differences among apricot jams for spreadability, texture, fruit pieces, flavor, off-flavor and overall quality but could not distinguish differences in sweetness and bitterness across cultivars. Results from this study provided much-needed information on sensorial profiles and physicochemical qualities of apricot jams made from these winter-hardy genotypes. We concluded that the best apricot for use in jam making is ‘Sungold’.

caffeic, chlorogenic and p- coumaric acids (Dragovic-Uzelac et al., 2007; Rababah et al., 2011). However, since apricots are cli- macteric fruit, high respiration rates, fast rip- ening and soft texture limit shelf life (Touati et al., 2014). Thus, apricots are frequently processed into dried fruits, jams, marma- lades, jellies or nectars (Touati et al., 2014).  The production of jellies and jams is a method used to preserve perishable fruits, which allows for consumption during peri- ods of the year when fresh fruit is not avail- able (Touati et al., 2014). Jams are classified as intermediate moisture foods, created by boiling whole fruit or pulp with pectin, acid, and sugars to a thick but spreadable consis- tency (Touati et al., 2014; Vidhya and Nara-

 Along with a number of other fruit and nut crops the apricot ( Prunus armeniaca L.) belongs to the large, economically impor- tant genus, Prunus L., part of the Rosaceae family (Potter, 2012). Prunus armeniaca are native to Asia (China) and have been bred and adapted for cultivation in areas that ful- fills the chilling requirements (Touati et al., 2014). World production of apricots was 4.04 M metric tonnes in 2012 and ranked 16 th in cultivated fruit worldwide (FAOSTAT 2013).  Apricots are aromatic, nutritionally rich fruits (Gutierrez-Martinez et al., 2007; Mehlenbacher et al., 1991) with a high fiber content, and a source of vitamins, minerals and sugars (Sartaj et al., 2011) as well as ca- rotenoids and phytochemicals, e.g. ferulic,

1 Graduate Research Assistant 2 Professor, to whom reprint requests should be addressed, email: ander044@umn.edu

3 Professor and Head 4 Research Scientist

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in, 2011; Kurz et al., 2008; Wicklund et al., 2005). Today, jam is a common and popular food product with 92% of households con- suming jams, jellies, and preserves (Agricul- ture and Agri-Food Canada, 2012).  Consumers’ perception of jam quality is affected by a number of physical, chemical, and sensory characteristics (Grujić et al., 2007). Sensory attributes perceived by the consumer during purchasing and consump- tion influence whether or not the product will be bought. According to Lawless and Hey- mann (2010), color is one of the most impor- tant sensory factors that consumers perceive when evaluating a food product’s quality. Other important sensory characteristics that have been examined when evaluating jam quality include taste, sweetness, sourness, spreadability, and overall quality (Culetu et al., 2014; Sandulachi and Tatarov, 2012; Touati et al., 2014). Previous studies exam- ining Prunus jam quality have also analyzed chemical and physical characteristics such as pH, soluble solids, titratable acid, and color parameters (Culetu et al., 2014; Sandulachi and Tatarov, 2012). Gelation, flavor, and shelf life of a jam are all affected by pH, which measures the amount of organic acid present in the sample (Culetu et al., 2014). The amount of sugar present in a jam is quan- tified via soluble solid content, which affects the gelation and stability of a jam (Culetu et al. 2014). Sucrose, pH and pectin are criti- cal components of jams to ensure gelling for spreadability and are routinely manipulated in jam recipes to ensure adequate gel struc- ture (Culetu, et al., 2014). Sugar binds water molecules, removing water away from pectin molecules which allows them to chemically link with each other and form polymeric net- work.  Although apricots are cultivated and en- joyed throughout the world, damage due to spring frosts and the lack of winter-hardy cultivars with good fruit quality limit the pro- duction of apricots in northern climates such as USDA Zones 3 and 4 (Mehlenbacher et al., 1991). Early breeding programs, includ-

ing the University of Minnesota, developed winter-hardy apricot hybrids by crossing commercial cultivars with hardy wild spe- cies (Anderson and Weir, 1967; Hoover et al. 2015). A number of hardy apricot hybrids, most notably ‘Moongold’ and ‘Sungold’, were developed using the Manchurian apri- cot ( P. mandshurica [Maxim.] Koehne) as a male parent (Anderson and Weir, 1967). The apricots ‘Brookcot’, ‘Debbie’s Gold’, and ‘Westcot’ are also considered winter-hardy cultivars (Ames, 2013). Although a number of hardy apricot selections and cultivars were introduced decades ago (Hoover and Zins, 1998), little is known about the quality of jam made from the fruits of these genotypes.  The objective of this paper was to quantify attributes of jams made from select USDA Zone 4 winter-hardy apricot genotypes from the University of Minnesota breeding pro- gram along with named comparisons. Spe- cifically, physicochemical properties and sensory profiles were examined to determine quantitative genotypic differences. Qualita- tive data, including the desire to purchase jams, were also evaluated. Materials and Methods  Genotypes and fruit harvest. During weeks 31-32 (2013) mature fruits from apricots P. armeniaca ‘Brookcot’, ‘Debbie’s Gold’, ‘Sungold’, ‘Westcot’ and unnamed selec- tions MN604, MN206, MN203, MN202 were harvested from trees at the University of Minnesota research plots in Excelsior, MN (44°52’06.5” N lat., -93°38’03.9” W long.). Week number is defined as the number of weeks from January 1 st , 2013. All trees in the research plots were managed for fruit pro- duction. Fruits were stored at 3-5 ° C no more than one week prior to pitting and jam prepa- ration. All apricot fruits were cut along the suture line with a pairing knife to remove the pit prior to jam preparation.  Jam preparation. Sugar and pectin were added to increase the concentrations in the harvested fruit mixture (Culetu, et al., 2014). Jams were made in sterilized dishes us-

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was washed with mild detergent and dried with a Kimwipe.  Titratable acidity (g/L) citric acid equiva- lent, a measure of the total amount of protons available, was determined by titrating a solu- tion containing 5 mL of jam and 50 mL of deionized water with 0.1 M NaOH (sodium hydroxide) to the endpoint of pH=8.20 us- ing an Thermo Scientific Orion 950 ROSS ® FAST QC™ Titrator with a Thermo Scien- tific Orion ROSS Sure-Flow pH electrode. Titrations were done in duplicate with all materials rinsed in between with deionized water. The pH of each sample was measured in triplicate using a Thermo Scientific Ori- on 950 ROSS ® FAST QC™ Titrator with a Thermo Scientific Orion ROSS Sure-Flow pH electrode. The electrode was rinsed with deionized water between measurements of the same sample, between samples the junc- tion was flushed and the electrode rinsed with deionized water .  Hue, lightness and color saturation angles for each sample were measured in triplicate for each jam sample using a Konica Minolta CR-400 chroma meter; data were expressed as L* a* b* color space or CIELAB where L* indicates lightness, higher values are lighter in color, and a* and b* are the chromaticity coordinates (Konica Minolta Sensing, Inc., 2003). Chromaticity coordinates a* and b* indicate the directions of color: +a* (red), -a* (green), +b* (yellow) and -b* (blue) with the center being “achromatic” (Konica Mi- nolta Sensing, Inc., 2003). Color saturation increases as a* and b* values increase in size. Chroma or saturation (C ab *) values were cal- culated using and are expressed as distance between the center, the “achromatic point”, and color (Gulrajani, 2010). Medium to high values of C ab * indicate bright or satu- rated color whereas lower values indicate duller or less saturated colors (Gulrajani, 2010). Hue angle (H ab ) expresses the angle measured beginning at the +a* axis (Konica Minolta Sensing, Inc., 2003). H ab was calcu- lated using Arctan (Gulrajani, 2010).  Sensory evaluation. Jams were evaluated

ing sterilized wooden, glass or non-reactive metal utensils in a semi-commercial, private kitchen (Kurz et al. 2008). All jams were made according to a standard recipe of 1.5 L (6.33 US cups) pitted fruit, 74 ml (5 US ta- blespoons) fresh-squeezed lemon juice, 14.2 g (1 US tablespoon) unsalted butter, 56.8 g (4 US tablespoons) Ball ® RealFruit ® Classic Pectin (Hearthmark, LLC dba Jarden Home Brands) and 1350 g (6 US cups) sugar. Pitted fruit were macerated using a hand-held puree machine (KitchenAid ® 2-Speed Immersion Hand Blender, #KHB1231) until fruit and skins were thoroughly pureed. Fruit, lemon juice, butter, and pectin were combined in an uncovered, non-reactive Revere ® copper- clad base stainless steel pot (4.26 L or 4.5 US quart), stirring constantly with a flat wooden spoon. The mixture was allowed to vigorous- ly boil for 1 minute. Sugar was then added, again stirring constantly until the jam began sheeting off from the flat, wide spoon. Each mixture was then removed from the heat source. The jam surface was skimmed to re- move any impurities and immediately poured into sterilized 0.24 L (0.5 US pint) glass jars and lids/rings were attached to the jars. Jars were inverted for 5 minutes and then reverted to upright position and cooled under a towel for 24 hours until sealed. Jars were labeled with the cultivar name and fruit type and stored at 12.8°C (55°F) in darkness for up to 6 months to maximize color retention and stability (García-Viguera, et al., 1999; Touati et al. 2014). Minimums of three jars of each cultivar were made for sensory evaluations.  Chemical analyses. Sugar content of the jams was measured in ° Brix using an Atago Digital Hand-held "Pocket" Refractometer PAL-2 (Cole-Parmer, Court Vernon Hills, IL). All measurements were made in tripli- cate (n=3 replications) with new samples placed on the refractometer each time. The refractometer was washed in between mea- surements with deionized water and dried with a Kimwipe (KIMWIPES™ Delicate Task Wipers, 11.2 cm x 21.3 cm or 4.4” x 8.4"). Between cultivars, the refractometer

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by a sensory panel made up of n=33 individuals of which 45% were female and 55% male, aged from their early 20s to 70s. Some of the panel members had sensory training and others had little to no sensory panel experience.  For the sensory session, all eight apricot jams along were randomized and assigned an alphanumeric code. While avoiding duplication, four codes were assigned to each evaluator’s seat. Each seat was also assigned each of three commercial jam standards for comparisons: Bonne Maman ® apricot preserves (apricot control; http:// www.bonnemaman.us/preserves-jellies/ apricot-preserves/), Bonne Maman ® cherry preserves (tart cherry control; http:// www.bonnemaman.us/preserves-jellies/

cherry-preserves/) and Bonne Maman ® plum preserves (plum control; http://www. bonnemaman.us/preserves-jellies/plum- preserves/) for a total of seven samples / evaluator. The tart cherry and plum controls were included to provide diversity of flavor and color. For statistical purposes, individual evaluators were considered incomplete blocks.  Jam jars were labeled with their corresponding code, and then approximately 15 g of each sample was placed in a neutral colored, 29.6 mL plastic, disposable, odor- free cup (Culetu, et al., 2014) labeled with the jam code, along with a 7.62 cm plastic taster spoon. These samples were placed at their corresponding seats along with one instruction (Fig. 1) and seven evaluation

Name________________________________

Taste the Difference! Sensory Evaluation 26 February 2014 Jams from the University of Minnesota Prunus Collection

You will be evaluating individual jam samples based on the ten criteria below. Please adhere to the following instructions as closely as possible and evaluate characteristics in the numbered order. ● Please taste the samples in order, from left to right ● Watch for pits! ● Write the code (on the side of sample cup) at the top of the evaluation sheet. 1. Color: Align the spectrum card with the bar scale on the scoring sheet - blue on the left, red on the right. Using the blank sheet of paper supplied, examine closely the color of the jam, and to the best of your ability match that color on the spectrum card. Draw a vertical mark through the bar scale at the point corresponding to the color on the spectrum card. 2. Spreadability: Using the spoon, move the jam back and forth in the cup, gauging its’ resistance to your movement. Using water as the thin extreme and frozen ice cream as the thick extreme, draw a vertical mark through bar scale at the point most accurately reflecting your impression. The following characteristics all require the jam to be placed in your mouth. You will not have enough of each sample to evaluate each characteristic with a separate mouthful. Therefore, please read through the instructions for criteria 3-10 before starting, so that you can evaluate numerous characteristics with each mouthful. You do not have to swallow the jam. The paper cup next to your water glass is a spit cup, if needed. 3. Texture: Move a small amount of jam around in your mouth. With your tongue, push the jam against the inside of your mouth paying close attention to the texture of the jam. Using pudding as a smooth extreme and gritty as the opposite extreme, make a vertical mark on the bar scale

J ournal of the A merican P omological S ociety The following characteristics all require the jam to be placed in your mouth. You will not have enough of each sample to evaluate each characteristic with a separate mouthful. Therefore, please read through the instructions for criteria 3-10 before starting, so that you can evaluate numerous characteristics with each mouthful. You d n t have to swallow the jam. The paper cup next to your water glass is a spit cup, if needed. 3. Texture: Move a small amount of jam around in your mouth. With your tongue, push the jam against the inside of your mouth paying close attention to the texture of the jam. Using pudding as a smooth extreme and gritty as the opposite extreme, make a vertical mark on the bar scale corresponding to your impression of the texture of the jam. 4. Fruit Pieces (if present): With a small amount of jam in your mouth, take note of the texture of any fruit pieces in the jam; bite down on one of the pieces. With melting as a soft extreme and citrus rind as a firm extreme, make a vertical mark on the bar scale corresponding to your impression of the texture of the fruit pieces. 5. Flavor: While moving a small amount of jam around in your mouth, take note of the intensity of fruit flavor. Is the flavor extremely strong and pronounced (intense) or is it barely perceptible or absent (none)? Make a vertical mark on the bar scale corresponding to your impression of the fruit flavor. 6. Off-Flavor: While moving a small amount of jam around in your mouth, take note of the intensity of any distracting or unpalatable flavor you would not normally associate with the corresponding fruit (cherry or plum). Is the flavor extremely strong and pronounced (intense), or is it barely perceptible or absent (none)? Make a vertical mark on the bar scale corresponding to your impression of the off-flavor. 7. Sweetness: While moving a small amount of jam around in your mouth, take note of the intensity of sweetness. Is the sensation of sweetness strong and overpowering (intense) or is it barely perceptible or absent (dry)? Make a vertical mark on the bar scale corresponding to your impression of the sweetness. 8. Bitterness: While moving a small amount of jam around in your mouth, take note of the intensity of bitterness. Is the sensation of bitterness strong and overpowering (intense) or is it barely perceptible or absent (none)? Make a vertical mark on the bar scale corresponding to your impression of the bitterness. 9. Overall Quality: What is your overall impression of the jam? Is it an enjoyable, well-balanced product, or do you find it distasteful or unpalatable? Make a vertical mark on the bar scale corresponding to your impression of the quality of the jam.

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10. Would you buy this? Exactly that - please circle either YES or NO.

Once you have finished evaluating this sample, cleanse your palate with water and eat one unsalted cracker and then proceed to the next jam. Rinse your mouth again, if necessary. Once you are finished please double check that you have written your name on the top of the packet and that the code for each jam is written on the top of each evaluation sheet.

Thank you for your participation.

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Jam Code______________

1. Color Blue

Red

2. Spreadability Easy (water) Moderate Firm (ice cream)

____________________________________________________________________________ Starting here, you will need to put the jam in your mouth. 3. Texture Smooth (pudding) Gritty

4. Fruit Pieces (if present) Soft (melting)

Moderate

Firm (citrus rind)

5. Flavor None

Moderate

Intense

6. Off-Flavor None Moderate

Intense

7. Sweetness Dry

Moderate

Intense

8. Bitterness None

Moderate

Intense

9. Overall Quality Poor

Average Excellent

10. Would you buy this jam?

Yes

No

Fig. 1. Sensory evaluation panel instructions used with the apricot jam taste tests.

sheets (Fig. 2), one color reference card, one neutral white and unlined 7.62 x 12.7 cm card, water cup, spit cup, and unsalted crackers (Fig. 3; Halat et al., 1997). All sensory evaluation panels were conducted at room temperature

to match the predominant conditions for jam consumption and conditions for previous panels (Culetu, et al., 2014).  Each group was given a brief, oral intro- duction on how to taste jams, palette cleans-

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Jam Code______________

1. Color Blue

Red

2. Spreadability Easy (water) 3. Mouth Feel Thin (water)

Moderate (Syrup)

Firm (ice cream) Thick (cream) Firm (citrus rind)

4. Fruit Pieces (if present) Soft (descriptor) Moderate

5. Flavor None 6. Off-­‐Flavor None 7. Sweetness Dry 8. Bitterness None

Moderate Moderate Moderate Moderate Average

Intense Intense Intense Intense

9. Overall Quality Poor (unpalatable)

Excellent

10. Would you buy this? YES

NO plemented with an unnumbered scalar range of seven boxes for recording scores (Fig. 2). All members of each group taste-tested the first sample (apricot control) together using the instructions (Fig. 1) and, once they had recorded their evaluative assessments of the

Fig. 2. Example score sheet used by each evaluator during the sensory evaluations.

ing procedures, use of the color chart ( cf. Fig. 3) and a review of the instruction (Fig. 1) and evaluation (Fig. 2) sheets. Amodifica- tion of the standard Hedonic 9-point (Law- less and Heymann, 2010; Basu et al. 2011) to 7-point scale (Grujić, et al., 2007) was im-

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Fig. 3. Setup of all items used in the sensory evaluation panels (see text)

apricot control, discussed the potential data points for each of the ten factors for each jam (Fig. 2). Sensory sessions took place in classroom settings with overhead cool white florescent lighting (538 Lux) and room tem- perature conditions (21°C). Each panelist was provided adequate space to evaluate his or her samples. However, physical barriers did not separate panelists.  Since evaluators marked the first nine sen- sory characteristics in the linear box plots (Fig. 2), these were transformed into quanti- tative data points, based on measuring (mm) from the beginning (far left-hand side) of the scale to wherever the panelist made their mark. This value was then divided by the to- tal length of the scale and then multiplied by ten to give data points on a ten-point scale.  Data Analyses. One-way Analysis of Vari- ance (ANOVA) as well as mean separations with Tukey’s Honest Significant Difference (HSD) tests a =0.05 were carried out for all quantitative data. Quantitative chemical analysis and ratings data were also analyzed

using principle components analysis. Quali- tative data, specifically desire to purchase, was analyzed using a Chi-square test with equal distribution across the two classes (1:1 c 2 ). Since there was only 1 degree of free- dom for the Chi-square test, the Chi-square correction of (Observed-Expected-0.5) 2 was used. Pearson’s Rank Correlations were car- ried out between variables. Results  Chemical analyses. Mean soluble solid concentration of jams ranged from 48.87° Brix for the tart cherry control to 68.47° Brix for MN604 (Table 1). The tart cherry control and ‘Westcot’ differed significantly for sol- uble solid concentration from all other jams (Table 1). In addition, MN604 differed sig- nificantly from both ‘Sungold’ and the cherry control (Table 1).  The range in mean pH values was 3.00 for MN604 and ‘Sungold’ to 3.35 for the tart cherry control (Table 1). The tart cherry con- trol pH differed significantly from all other

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Table 1. Mean soluble solids (S.S.; °Brix), pH, titratable acidity (T.A.; g/L citric acid equivalent), L*a*b* color space or CIELAB (where L* indicates lightness; a* and b* are the chromaticity coordinates), hue angle (H ab * = arctan(b*/a*) and chrome (C ab *= sqrt [a* 2 +b* 2 ]) for apricot, tart cherry and plum jams used in the sensory evaluation panel. Mean separations within traits (columns), based on Tukey's 5% HSD. S.S. Color Jam (°Brix) pH T.A. L* a* b* H ab * C ab * Tart cherry control 48.87 c 3.35 a 7.29 f 29.93 bc 13.18 abc 4.11 d 0.32 e 13.84 d Plum control 65.87 ab 3.23 b 8.44 f 24.62 c 17.70 a 10.13 d 0.52 d 20.39 cd Apricot control 67.30 ab 3.20 bc 12.37 de 41.24 a 16.44 ab 38.71 a 1.17 bc 42.06 a MN604 68.47 a 3.00 f 16.23 ab 39.71 ab 13.22 abc 31.05 abc 1.17 bc 33.79 ab MN206 65.50 ab 3.15 cd 11.74 e 38.44 ab 14.16 ab 27.65 bc 1.10 c 31.07 abc MN203 61.57 ab 3.02 ef 15.41 abc 36.89 ab 14.83 ab 30.71 abc 1.10 c 34.55 ab MN202 66.50 ab 3.12 d 14.17 cd 44.88 a 8.53 c 29.89 abc 1.29 a 31.10 abc ‘Brookcot’ 64.93 ab 3.01 f 14.54 bc 46.25 a 8.71 c 31.49 abc 1.30 ab 32.68 ab ‘Debbie’s Gold’ 64.37 ab 3.11 d 15.17 bc 42.06 a 13.51 abc 38.78 a 1.24 ab 41.07 a ‘Sungold’ 59.77 b 3.00 f 14.41 c 41.45 a 12.27 bc 35.93 ab 1.24 a 38.00 a ‘Westcot’ 50.70 c 3.06 e 17.60 a 42.73 a 8.93 c 23.57 c 1.21 ab 25.09 bc

significantly lighter than the plum control but overlapped with the tart cherry control.  The chromaticity coordinates for green- red (a* values) ranged from a*=8.53 units for MN202 to a*=17.70 units for the plum con- trol, which had the “reddest” color (Table 1). The plum control differed significantly from MN202, ‘Brookcot’, ‘Sungold’ and ‘West- cot’ for the green-red coloration; the apricot control, MN206, and MN203 were signifi- cantly different than MN202, ‘Brookcot’ and ‘Westcot’ for a* (Table 1). All other jams had intermediate a* values (Table 1). Chro- maticity coordinates for blue-yellow (b*) varied from b*=4.11 (tart cherry control) to b*=38.78 (‘Debbie’s Gold; Table 1). The jam with the “yellowest” or least coloration satu- ration chromaticity coordinates was ‘Deb- bie’s Gold’, which was significantly different than both the tart cherry and plum controls as well as MN206 and ‘Westcot’ (Table 1). The plum and tart cherry controls differed for b* from all apricot accessions, including the apricot control (Table 1).  Hue angles, H ab *, were distributed from 0.32 (tart cherry control) to 1.30 (‘Brookcot’; Table 1) with significant variation among genotypes . The plum and tart cherry controls

jam types whereas the plum control differed significantly from all jams except for the apricot control (Table 1). MN206 was sig- nificantly different from the majority of other jams’ pH values except for the apricot con- trol, MN202, and ‘Debbie’s Gold’ (Table 1). ‘Westcot’ was significantly different than the majority of jams except for MN203. Apricot jams from MN604, MN203, ‘Brookcot’, and ‘Sungold’ were not significantly different from each other but differed from the remain- ing jams for pH (Table 1).  There was significant variation among the apricot jams for titratable acidity . The titrat- able acidity ranged widely, from 7.29 ml (tart cherry control) to 17.60 ml for ‘Westcot’ (Table 1). Both the plum and tart cherry con- trols were significantly different than all of the other jams in this study.  Color lightness (L*) ranged from the dark- est L*=24.62 (plum control) to the light- est (L*=46.25 for ‘Brookcot’; Table 1). As would be expected with lighter colored or yellower apricots, the darkest jams (plum and tart cherry controls) did not differ from each other in L* values or most other jams tested (Table 1). The only exceptions were MN604, MN206, and MN203 (Table 1), which were

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The pooled mean rating for sweetness was 6.2 and 1.9 for bitterness (data not shown).  Mean ratings for color in the sensory eval- uations (10 point scale) ranged from 5.3 for MN206 to 8.8 for the tart cherry control; all apricot jams differed significantly from the plum and cherry controls (Table 2). Spread- ability mean ratings ranged from 4.2 (plum control) to 8.5 (MN206) with the tart cherry and plum controls differing significantly from only MN206 (Table 2).  Texture ratings ranged from 3.4 for the plum control to 8.7 for ‘Brookcot’ jams (Ta- ble 2). ‘Brookcot’ jam differed significantly from all other jams except for MN604; like- wise, MN604 differed significantly from all other jams except for MN206 (Table 2). In addition to being significantly different from ‘Brookcot’, MN206 also differed from both the tart cherry and plum control jams (Table 2).  The mean ratings for fruit pieces in the jams ranged from 3.9 for the apricot control to 7.1 for MN604 (Table 2) with a higher presence of solids. MN604’s mean fruit pieces rating was significantly different than the apricot and tart cherry controls as well as ‘Westcot’ (Table 2). ‘Brookcot’ differed significantly from the tart cherry and apricot controls (Table 2).

were significantly different than all apricot jams for hue angles (Table 1). There was sig- nificant variation among the apricot jams for hue angle with MN202 and ‘Sungold’ differ- ing significantly from the majority of other genotypes except for ‘Brookcot’, ‘Debbie’s Gold’, and ‘Westcot’ (Table 1). In addition, ‘Brookcot’ and ‘Debbie’s Gold’ were signifi- cantly different than about half of the other *) values ranged wide- ly from 13.84 for the tart cherry control to 42.06 for the apricot control (Table 1). The tart cherry and plum controls did not differ significantly from each other; the tart cherry control chrome values differed significantly from all jams with the exception of the plum control. The plum control C ab * values differed significantly from the apricot control, MN604, MN203, ‘Brookcot’, ‘Debbie’s Gold’, and ‘Sungold’ (Table 1). ‘Westcot’ jam differed significantly from the apricot control, ‘Deb- bie’s Gold’, and ‘Sungold’ (Table 1).  Sensory evaluations. There was significant variation among jams for color, spreadabil- ity, texture, fruit pieces, flavor, off-flavor, and overall quality in this study (p<0.05). In contrast, for the sweetness and bitterness rat- ings there was no significant variation among genotypes (p=0.09 and p=0.48, respectively). genotypes (Table 1).  Mean chrome (C ab

Table 2. Mean color, spreadability, texture, fruit pieces, flavor, off-flavor, and overall quality ratings (10 point scale) for apricot jams and tart cherry/plum controls as determined by sensory panelists (n=33). Mean separations within significant traits (columns), based on Tukey's 5% HSD. Spread- Fruit Off Overall Jam Color ability Texture Pieces Flavor Flavor Quality Tart cherry Control 8.8 a 4.8 b 3.5 d 4.0 c 6.4 bc 0.9 c 7.0 a Plum Control 8.2 a 4.2 b 3.4 d 5.2 abc 6.0 c 1.7 abc 5.6 b Apricot Control 5.7 b 5.9 ab 3.9 cd 3.9 c 6.4 bc 1.7 abc 6.3 ab MN604 6.0 b 6.0 ab 6.9 ab 7.1 a 7.4 bc 2.8 a 5.7 ab MN206 5.3 b 8.5 a 5.3 bc 5.1 abc 6.3 abc 1.7 abc 5.8 ab MN203 6.0 b 5.7 ab 4.9 cd 5.2 abc 7.3 abc 2.4 ab 6.7 ab MN202 5.5 b 5.6 ab 4.7 cd 5.9 abc 7.1 abc 1.4 abc 6.1 ab ‘Brookcot’ 5.4 b 6.4 ab 8.7 a 6.4 ab 6.0 c 2.2 abc 3.6 c ‘Debbie’s Gold’ 5.4 b 5.8 ab 4.8 cd 5.5 abc 7.6 ab 1.7 abc 6.4 ab ‘Sungold’ 5.6 b 5.2 ab 4.7 cd 5.5 abc 7.1 abc 1.0 bc 6.8 ab

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 Sensory evaluation ratings for flavor var- ied from 6.0 for ‘Brookcot’ and the plum control to 8.1 for ‘Westcot’, with the latter differing significantly from the cherry, plum, and apricot controls as well as MN604 and ‘Brookcot’ (Table 2). The mean rating for fla- vor of ‘Debbie’s Gold’ jam differed signifi- cantly from the plum control and ‘Brookcot’.  Off-flavor ratings for all jams were rela- tively low with mean ratings ranging from 0.9 for the cherry control to 2.7 for ‘West- cot’ (Table 2). Apricot jams from MN604 and ‘Westcot’ differed significantly from ‘Sungold’ and the tart cherry control (Table 2). MN203 apricot jam also was significantly different than the cherry control (Table 2).  The wide range in sensory evaluation val- ues for overall quality was 3.6 for ‘Brookcot’ to 7.0 for the cherry control (Table 2). The tart cherry control differed significantly from the plum control, ‘Westcot’, and ‘Brookcot’ jams for overall quality (Table 2). ‘Brookcot’

had significantly lower overall quality rat- ings than all other jams, particularly the con- trol comparisons (Table 2).  Correlations. The correlation matrix (Ta- ble 3) shows chemical and sensory evalua- tion trait combinations that were either posi- tively or negatively correlated. Color ratings were positively and significantly correlated with overall quality, desire to purchase, pH, and negatively but significantly correlated with texture, fruit pieces, titratable acidity, L*, b*, H ab *, and C ab * (Table 3).  Texture ratings were positively and signifi- cantly correlated with fruit pieces, off-flavor, soluble solids, H ab * but texture was nega- tively correlated with overall quality, desire to purchase, and pH (Table 3). Fruit pieces were positively and significantly correlated with flavor, off-flavor, bitterness, and soluble solids whereas fruit pieces were negatively, but significantly correlated, with overall quality (Table 3).

Table 3. Correlations between parameters color, texture (Text.), fruit pieces (Pieces), falvor (Flav.), off-flavor (Off-Flav.), sweetness (Sweet.), bitterness (Bitter.), and over quality (Quality) ratings, desire to purchase (Purch.) and soluble solids (S.S.), pH, titratable acidity (TA), hue directions L*, a*, b*, H ab *, and C ab * for all jams tested. An asterisk (*) indicates a signficant correlation coefficient (<0.05). Off Hue directions Color Text. Pieces Flav. Flav. Sweet. Bitter. Quality Purch. S. S. pH TA L* a* b* H ab * C ab * Color 1.00 Text. -0.25* 1.00 Pieces -0.15* 0.47* 1.00 Flav. -0.06 0.04 0.14* 1.00 Off-Flav. -0.06 0.26* 0.16* 0.18* 1.00 Sweet. 0.10 0.02 0.00 0.11 -0.03 1.00 Bitter. 0.00 0.26* 0.32* 0.20* 0.37* -0.25* 1.00 Quality 0.18* -0.29* -0.15* 0.29* -0.26* 0.12 -0.23* 1.00 Purch. 0.17* -0.20* -0.11 0.28* -0.19* 0.13 -0.15* 0.73* 1.00 S.S. -0.33 0.44* 0.64* -0.24 0.34 -0.10 0.27 -0.33 -0.16 1.00 pH 0.70* -0.39* -0.30 -0.10 -0.23 -0.07 -0.16 0.02 0.09 -0.30 1.00 TA -0.82* 0.40 0.22 0.09 0.27 0.10 0.11 -0.07 -0.04 0.34 -0.86* 1.00 L* -0.76* 0.28 -0.07 0.13 0.18 0.09 0.21 -0.02 0.04 0.15 -0.59* 0.66* 1.00 a* 0.34 -0.29 0.26 -0.14 -0.09 -0.20 -0.08 0.02 0.08 0.25 0.35* -0.32 -0.73* 1.00 b* -0.82* 0.27 0.29 0.05 0.22 -0.11 0.21 -0.02 0.10 0.50* -0.65* 0.75* 0.67* -0.06 1.00 H ab * -0.90* 0.37* 0.15 0.11 0.22 0.04 0.15 -0.05 -0.01 0.39* -0.79* 0.86* 0.86* -0.45* 0.88* 1.00 C ab * -0.71* 0.23 0.34 0.00 0.20 -0.17 0.20 -0.01 0.11 0.54* -0.54* 0.67* 0.48 0.15* 0.90* 0.75* 1.00

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stating they would purchase and 18.2% stat- ing they would not (χ 2 value=6.1; Table 4). Chemical Analysis PCA. The first two prin- cipal components for the chemical analysis data, PC1 and PC2, had eigenvalues ≥ 1.0 and, together, accounted for 80.9% of the variation. PC1 accounted for 59.1% of the variation and was positively associated with a*, soluble solid content, C ab *, b*, and pH (Fig. 4A). PC1 was negatively associated with L*; PC2 accounted for 21.8% of the variation and was positively associated with soluble solids, C ab *, b*, titratable acid, H ab *, and L* (Fig. 4A). PC2 was negatively associ- ated with a* and pH. The majority of apricot jams were positively associated with PC1 and PC2; ‘Westcot’ was negatively associ- ated with PC1 (Fig. 4A). The plum control was positively associated with PC1 and neg- atively associated with PC2; the tart cherry control was negatively associated with both principle components (Fig. 4A).  Sensory Evaluation Ratings PCA. The first four principal components (PC1, PC2, PC3, and PC4) had eigenvalues ≥ 1.0 and account- ed for 64.9% of the variation. PC1 accounted for 25.2% of the variation and was positively associated with all ratings except for texture and spreadability (Fig. 4B). The fruit pieces, bitterness, and off-flavor variable vectors were closely clustered on the PCA biplot (Fig. 4B). Flavor, off-flavor, fruit pieces,

 Flavor ratings were positively correlated with off-flavor, bitterness, overall qual- ity, and desire to purchase. Off-flavor rating was positively correlated with bitterness and negatively correlated with overall quality and the desire to purchase (Table 3). As would be expected, sweetness ratings were negatively correlated with bitterness. The bitterness rat- ings were negatively correlated with over- all quality and desire to purchase (Table 3). Overall quality was also positively correlated with desire to purchase.  Unexpectedly, soluble solid concentration was positively correlated with hue direc- tions b*, H ab *, and C ab *. pH was positively correlated with a* but negatively correlated with titratable acidity, L*, b*, H ab *, and C ab * (Table 3). In addition, titratable acidity was positively correlated with L*, b*, H ab *, and C ab * (Table 3). Hue L* was positively corre- lated with b*, H ab *, and negatively correlated with a* (Table 3). In addition, a* was posi- tively correlated with C ab *. Hue direction b* was positively correlated with H ab * and Cab. Finally, H ab * and C ab * were positively corre- lated with each other (Table 3).  Chi-square. The expected χ 2 ratio of will- ingness to purchase or not (yes:no) was 1:1. For the majority of jams, the ratio did not dif- fer significantly from the expected. Only the tart cherry control differed significantly from the expected ratio with 81.8% individuals

Table 4. Chi-square tests of the desire to purchase (sensory evalution) for each jam type tested (1:1χ 2 ). Chi-square (χ 2 ) was corrected by (Observed-Expected-0.5) 2 due to the fact there was only 1 degree of freedom (df=1). Jam tested % Yes % No χ 2 Tart cherry Control 81.8 18.2 6.1* Plum Control 45.5 54.5 0.2 Apricot Control 60.6 39.4 0.5 MN604 37.5 62.5 0.8 MN206 66.7 33.3 0.5 MN203 83.3 16.7 3.4 ‘Brookcot’ 25.0 75.0 2.5 ‘Debbie’s Gold’ 50.0 50.0 0.0 ‘Sungold’ 73.3 26.7 1.2 ʻWestcotʼ 50.0 50.0 0.0

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bitterness, texture, and spreadability ratings were positively associated with PC2 whereas overall quality, sweetness, and color were negatively associated with PC2 (Fig. 4B). Most jams, except for the apricot control, ‘Brookcot’, MN206, and the plum control, were positively associated with PC1 (Fig. 4B). Most jams were positively associated with PC2 except for the three controls (Fig. 4B). Discussion  The pH values for the apricot jams and comparisons in the present study (Table 1) were similar to those reported by Aslanova et al. (2010). Apricot jams tested by Touati et al., (2014) had higher values (pH=3.54) prior to storage of the jams. Titratable acidity lev- els in the jams tested herein were similar to previous reports as well (Touati et al., 2014;

Aslanova et al., 2010). The significantly low- est pH values found in MN 604, MN203, ‘Brookcot’ and ‘Sungold’ apricot jams could mean increased protection against the devel- opment of microorganisms over time (Touati et al. 2014), although this was not tested. Lightness (L*) is also an important factor in non-enzymatic browning (Touati et al., 2014), although L* and pH were negatively and significantly correlated for the 11 tested jam samples (Table 3).  ‘Sungold’, ‘Westcot’ and the tart cherry jam control all had <60% soluble solids (°Brix; Table 1), which is the minimal level required by the Codex Alimentarious Stan- dard (CODEXSTAN, 2009). All other apricot jams tested met the CODEXSTAN minimum soluble solid level and were similar to previ- ous findings for other apricot (Touati et al., 2014) and quince jams (Ferreira et al., 2014).

Biplot of variables and individuals chemical analysis PCA

a.

Groups

2

'Brookcot'

Soluble.Solids

'Debbie's Gold'

Cab

'Sungold'

1

b.

'Westcot'

pH

apricot control

0

Titratable.Acid

Hab

cherry control

MN202

Dim2 (21.8%)

−1

L.

MN203

MN206

−2

MN604

plum control

−3

−6

−4

−2

0

2

Dim1 (59.1%)

Fig. 4A.

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Biplot of variables and individuals ratings PCA

4

flavor

Groups

overall.quality

'Brookcot'

'Debbie's Gold'

2

sweetness

'Sungold'

color

bitterness

'Westcot'

fruit.pieces off.flavor

apricot control

spread

texture

0

cherry control

MN202

Dim2 (15.1%)

MN203

−2

MN206

MN604

plum control

−4

−2

0

2

4

Dim1 (25.2%)

Fig. 4. Biplots from principal components analyses measured variables for the apricot jams and comparisons used in the (A) chemical analysis for mean soluble solids, pH, titratable acidity (g/L citric acid equivalent) L*a*b* color space or CIELAB (where L* indicateslightness; a* and b* are the chromaticity coordinates), hue angle (H ab * = arctan(b*/a*) and chrome (C ab * = sqt [a* 2 +b* 2 ]) and (B) sensory evaluation panels for fruit pieces, flavor, off-flavor, sweetness, color and overall quality (10-point scale); spreadability, texture and bitterness ratings on a 0 to 10 scale.

 Apricot jam color, as gauged by color lightness (L*), is one of the most important consumer selection criteria (Touati et al., 2014). L* was the lightest for ‘Brookcot’ jam (Table 1). The panelists in the sensory evaluation were also able to discern differ- ences among the apricot jams and their com- parisons for color (Table 2). Since apricot fruits range in colors of yellow to orange and red when ripe, chromaticity coordinates of blue-yellow (b*) indicate that ‘Debbie’s Gold’ was the yellowest apricot jam and sig- nificantly yellower than MN206, ‘Westcott’, the tart cherry and plum controls (Table 1). In contrast to ‘Brookcot’, apricot jams made

from MN604, MN206 and MN203 were sig- nificantly darker in color and were statisti- cally similar to the tart cherry control. Such darker-colored apricot jams, changing from yellower to more reddish tones may be due to the Maillard reaction whereby brown pig- mentation is formed or enzymatic browning occurs. The browning of jams has been ob- served in previous studies of apricot (Touati et al., 2014) and strawberry jams (Wicklund et al., 2005; Patras et al., 2011).  The panelists in the sensory evaluation were able to discern differences among the apricot jams and comparisons for spread- ability, texture, fruit pieces, flavor, off-flavor

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and overall quality (Table 1). For the spread- ability scores, MN206 had the most similar value (8.5) reported in other studies (range of 7.0-8.11; Touati et al. 2014). Panelists could not distinguish differences for sweetness and bitterness ratings for any of the jams (data not shown). Thus, even if fructose or glucose levels in the fresh fruit differed, the addition of comparative sucrose levels during the jam making process may have masked such dif- ferences, if they existed. Future chemical research could identify whether or not fruc- tose and/or glucose levels differ in the apricot cultivar jams tested herein. Likewise, future studies could include testing storage effects on all parameters to determine whether jam quality changes over time.  Oftentimes panelists in sensory evalua- tions are unable to discriminate for specific traits among jam samples. For example, some apricot jams are admixtures with un- declared additives such as apples (Drugov- ic-Uzelac et al., 2005b), pumpkin (Drugov- ic-Uzelac et al., 2005a) or sugar and water (Fuchs and Koswig, 1997; Hammond, 1997). Such additions occur due to the high cost of fresh apricot fruit, limited production or crop failures. Sensory evaluation panelists could not detect these adulterations in apricot jams (Drugovic-Uzelac et al., 2005b).  One unnamed apricot selection, MN 206, had the highest number of traits (5 in total) that differed significantly from other tested apricot jams. MN 206 had low T.A. and high scores for spreadability, texture, fruit pieces, flavor and overall quality. However, since MN 206 is not on the market and unavailable to consumers, the second tier of high quality apricot jams were made from ‘Sungold’ and ‘Brookcot’. Both of these cultivars had sig- nificantly lower pH, which ensures long-term storage and has a lower likelihood of brown- ing from the Maillard reaction, while ‘Sun- gold’ had <60% soluble solids as required by the Codex Alimentarious Standard. ‘Sun- gold’ also rated high in overall quality, T.A., and 73.3% of the sensory evaluation panel- ists said they would purchase this apricot

jam. This is in contrast to ‘Brookcot’ where 75% of the panelists would not purchase it (Table 4). Thus, we recommend ‘Sungold’ as the best apricot for making jam with the currently available winter hardy trees for purchase. Acknowledgements  Funding in support of this publication was a grant from the Minnesota Landscape Arbo- retum Land Grant Chair and the Minnesota Agricultural Experiment Station. Literature Cited Agriculture and AgriFood Canada. 2012. Sweet Spreads in the United States. International Markets Bureau Market Indicator Report. http://www.agr. gc.ca/eng/industry-markets-and-trade/statistics- and-market-information/agriculture-and-food-mar- ket-information-by-region/united-states-and-mex- ico/market-intelligence/sweet-spreads-in-the-unit- ed-states/?id=1410083148480 Accessed: 5/18/2016 Ames, G. and R. Maggiani. 2013. Plums, apricots, and their crosses: Organic and low-spray production. ATTRA. www.attra.ncat.org, IP386, Slot 38, Ver- sion 052213. Accessed: 11/18/2016. Andersen, E. T. and T.S. Weir. 1967. Prunus hybrids, selections and cultivars, at the University of Min- nesota Fruit Breeding Farm. Minnesota Agricultural Experiment Station. University of Minnesota Digital Conservancy, http://hdl.handle.net/11299/140015 Accessed 4/10/2016. Aslanova, D., E. Bakkalbasi, and N. Artik. 2010. Ef- fect of storage on 5-hydroxymethylfurfural (HMF) formation and colour change in jams. Int. J. Food Properties 13:904-912. Basu, S., U.S. Shivhare, T.V. Singh, and V.S. Beniw- al. 2011. Rhenological, textural and spectral charac- teristics of sorbitol substituted mango jam. J. Food Eng. 105:503-512. CODEXSTAN. 2009. Codex standard for jam, jellies and marmalades. www.codexalimentarius.org Ac- cessed 4/10/2016. Culetu, A., F.A. Manolache, and D.E. Duta. 2014. Ex- ploratory study of physicochemical, textural and sensory characteristics of sugar-free traditional plum jams. J. Texture Studies 45:138-147. Dragovic-Uzelac, V., J. Pospišil, B. Levaj, and K. De- longa. 2004. The study of phenolic profiles of raw apricots and apples and their purees by HPLC for the evaluation of apricot nectars and jams authentic- ity. Food Chem. 91:373-383. Dragovic-Uzelac, V., K. Delonga, B. Levaj, S. Djakov-